1. Field of the Invention
The present invention is generally directed to location information systems, and more particularly to location information systems that use multiple positioning technologies.
2. Background Art
Positioning technologies for determining the location of an object are well known. For example, the Global Positioning System (GPS) includes a constellation of orbiting satellites. A GPS receiver uses signals from these satellites to determine its location, speed/direction, and time.
Radar is another positioning technology that uses electromagnetic waves to identify the range, altitude, direction, and speed of both moving and fixed objects such as aircraft, ships, motor vehicles, weather formations, and terrain.
A variety of location-related applications exist that use such positioning technologies. For example, truck tracking systems exist which employ GPS technology to track trucks as they travel through the country.
However, a location-related application typically employs only a single positioning technology. The use of a single positioning technology is a disadvantage as it is subject to single point of failure outages. The use of a single positioning technology is also a disadvantage because it is often difficult for any given positioning technology to provide complete coverage of any given area of interest.
Existing location-related applications are also flawed because they do not inherently support the addition of other positioning technologies. For example, a GPS based application (such as the truck tracking example mentioned above) cannot easily be modified to add devices that are based on radio-frequency identification (RFID) positioning technology. Instead, such modification is typically only possible through a time consuming and costly system overhaul. Such inflexibility of existing location-related applications make them ill-suited for enterprises that must be able to adapt quickly and inexpensively to changes in mission and positioning technologies.
Therefore, what is needed are improved location information systems, methods and computer program products that are capable of employing multiple positioning technologies.